j10 360/Carb

[GratefulTread]

My 82 j10, running a 360, Edelbrock Performer manifold and a Holley 4160... started idleing rough, and mileage went to hell.
Took it to a reputable local shop, and they did a service on the carb, tech said the "power valve" was blown out and dumping gas into the carb. Also said it was a bitch to get it running smooth...but then it ran GREAT! Gas mileage beyond anything I'd imagined, good power (Great power!), girls smiling at me....you know, pro service. OK, money well spent.

Four or five weeks later it started again, now it won't idle, diesels, run fine with throttle, but black smoke if you gas it in neutral (runs a bit smoother out of gear, TF727).

Bad carb? I can get an Edelbrock Performer 1411, 750cfm, which looks to be overkill (oversized?) for this manifold, but it is new and a good price (cheaper than a 650, which is what E says is right for the manifold).

Will it work? Is there a better choice? Should I just feed this beast dollar bills...sorry, I digress.

The giant thing is wearing me down, can't fix it fast enough to get it just running.

Any ideas? Any buyers? Just kidding... :razz:

[jeepsr4ever]

Dieseling and black smoke...hmm. Sounds like timing..could be the power valve blew out again.

[AMX69PHATTY]

yeah, power valve again, did it ever backfire since it ran good ? a backfire can damage the power valve, unless it's a newer holley which are supposed to have power valve blowout protection. One thing good about Edelbrocks, they do NOT have a power valve that can get blown out. A 750 Eddy carb would be ok on a 360. They're basically vacuum secondary carbs and "self compensate" for engine size. The newer "Thunder Series" ( I think ) have adjustable secondary opening.

[Goose]

I agree sounds like the power valve again..
I would also agree that the Edel brock carbs are a great choice (I would use the 1406 600 or 650 cfm) but either would work well on the 360..

This power valve issue you are experiencing is one of the major flaws in the holley carb..and is probably the reason that more people get aggravated with them.. I thought they redesigned it so it couldnt blow the P/V any more..?

[GratefulTread]

Thanks for the input...

There was a bit of backfire, some popping out the exhaust on decel, but I don't remember any dramatic event through the carb. It seems likely I did have a timing issue.

I don't have a Holley rebuild manual, so I was a bit freaked out by the exploded view (last carb I rebuilt was German aircooled, like fixing a toilet plunger) but I found a good article on on of the hot rod mag websites that was about changing out the valve, so I gave it a shot. It looked to easy, and it was, but no change. The article mentions that they tested valves that were bad out of the box, seems a little unlikely; but if those things are that sensitive I think I am going to give the Edelbrock a try.

[mike4089]

if you have a 750 on there it might be to big...i had a 750 on my mildly built 360 and it was to big stepped down to a 650 and it was like night and day...best money ive spent on that motor so far was a new carb...

[GratefulTread]

Crud... :sa: just called and arranged the buy... #-o

That's sorta what I wanted to know...define "too big".

The price new-in-box is $200, way cheaper than I'd seen the 600/650's. Looked at the Edelbrock site, they say OK for 360, but not so much w/Performer intake. I figured it would just be overkill, not a downgrade... :(:

I'd really just like it to start, roll & run. I just can't seem to get there from here.

[GratefulTread]

I finally got through to Edelbrock, and they say the Performer 750 #1411 will not work with the Performer manifold; sluggish off the line and it will bog down when you hit the throttle, impossible to fix. They say that it will work with the Air Gap manifold, they recommend the Performer 600 #1405/6 for daily driver or the Thunder AVS 650 #1805/6 for best performance.

I was looking for the quick easy way, but that doesn't really seem like my style... :roll:

What model # is the Remanufactured Edelbrock here in the store? Any downside in putting the offroad kit in an occasional offroad only truck?

[dbesade]

I finally got through to Edelbrock, and they say the Performer 750 #1411 will not work with the Performer manifold; sluggish off the line and it will bog down when you hit the throttle, impossible to fix. They say that it will work with the Air Gap manifold, they recommend the Performer 600 #1405/6 for daily driver or the Thunder AVS 650 #1805/6 for best performance.

I was looking for the quick easy way, but that doesn't really seem like my style... :roll:

What model # is the Remanufactured Edelbrock here in the store? Any downside in putting the offroad kit in an occasional offroad only truck?

I run a 1406 600CFM Performer on a Performer Intake on my 304.. runs a bit rich but runs well should be fine on a 360.

-Dave

[1980_Cj7]

Interesting. We're running an Edelbrock Performer 750 on a Performer intake on the 401. Now Edelbrock is saying it isn't good on that manifold??? Are they saying it is too big for the 360, or just not a good match with that intake?

[jeepsr4ever]

Thats just one tech opinion and was it based on a camshaft? I wouldnt hesitate to run a 600cfm on a 360 or a 750cfm on a 360 or 401 depending on the condition of the motor.

[GratefulTread]

He said too big for the manifold. He said it would lag off the line and under full throttle acceleration would sag to the point of stalling, and it couldn't be adjusted away. Something about the secondaries being counterbalanced...My carb theory understanding is not deep, but he was pretty convincing.

[scrible88]

I have a 750 edelbrock on an edelbrock performer intake and my motor is in for a rebuild right now, but before when it was completely stock and ran well the 750 with performer manifold was a great combo for the motor... tons of power... I don't know what their deal is saying it is too big for the 360 because it isn't at all based on my experience...

here's a video of my motor with the edelbrock 750 and performer intake before the oil pump decided to go south on me:

http://smg.photobucket.com/albums/v156/sandstormII/?action=view&current=burnout.flv

[Goose]

At the risk of getting in trouble with some of the guys around here.. There is a formula out there that calculates CFM based on cubic inches..etc but based on practical theory.. a 530 cfm carb will feed 350 cubic inches at 6500 rpm. some guys run bigger carbs and get away with it.. the truth is simple.

If you choose the correct CFM you can jet up to match fuel flow..

[jeepsr4ever]

At the risk of getting in trouble with some of the guys around here.. There is a formula out there that calculates CFM based on cubic inches

Plus 30% is what major carb mfgs suggest

[1980_Cj7]

Goose, so what is the formula, or do you know where I can find it?

[AMX69PHATTY]

The problem is that the carb makers do not tell at what pressure drop thier CFM ratings are taken at, they all use different rating methods.

[1980_Cj7]

So they don't have an ".050 kinda deal" like the cam guys do so you can comparison shop, huh.

[82Waggy]

(CID/3456)*RPM = CFM @ Volumetric Efficiency of 100%


CID RPM VE=100% VE=95% VE=90% VE=85% VE=80% CID RPM
360 4500 469 445 422 398 375 360 4500
360 5000 521 495 469 443 417 360 5000
360 5500 573 544 516 487 458 360 5500
360 6000 625 594 563 531 500 360 5800
360 6500 677 643 609 576 542 360 6000
360 7000 729 693 656 620 583 360 6500

When in doubt, go smaller.

[a440plus6]

I finally got through to Edelbrock, and they say the Performer 750 #1411 will not work with the Performer manifold; sluggish off the line and it will bog down when you hit the throttle, impossible to fix. They say that it will work with the Air Gap manifold, they recommend the Performer 600 #1405/6 for daily driver or the Thunder AVS 650 #1805/6 for best performance.

I was looking for the quick easy way, but that doesn't really seem like my style... :roll:

What model # is the Remanufactured Edelbrock here in the store? Any downside in putting the offroad kit in an occasional offroad only truck?
It will work fine if you fiddle with jets, springs and rod.
I'm not sure but I think you might have to lighten up the velocity flapper a little or just put on from a 625cfm carb in if you ar not used to tuning them.

[GratefulTread]

Well, I broke down and installed the Performer 1406...600CFM & electric choke; bolted on and it fired right up. Runs at idle smooth without tweaking, and great acceleration, it all works!

Except...and I hate this, it sounds too stupid... the air filter stud doesn't thread into anything! #-o I can't see any threads in the hole it should sit in, and it doesn't catch threads at the bottom of the hole, and shining a little light in there I don't see anything threaded...what the hell? It isn't the wrong size, the wingnut from the old stud on the Holley screws on either side of the stud, so not stripped. The install video and paperwork just say basically screw it in and cut off the excess.

I hope this is just me missing something painfully obvious, or a weird manufacturing defect, but I guess I have another call to Edelbrock to make.

JB Weld... :-| maybe that would work....

[1980_Cj7]

JB Weld... :-| maybe that would work....

Right up until the first time you have to take the top off the carb to change jets or squirters or rebuild it.

Did it come with a threaded rod/stud? I had trouble finding one to fit our 750 Performer. I tried several different sizes and even metric. Forget what finally fit. If I recall, there are two size threads down in the carb, a larger size up top, then a smaller threaded hole further down below that. Or am I hallucinating again from breathing too much carb cleaner ?

[GratefulTread]

Yeah, the rebuild, can't wait for that...no glue....

Yes. it came with a 5 inch threaded stud that looks like it should just screw right into the center hole. The old wing nut fits it just fine but it doesn't hook up, or even feel like it's cross threaded, nothing. I already mounted it in the truck (and I can't quite get in the engine far enough to really see what's happening down in there), hate to take it out again but that's obviously about to happen again. :smile:

I've either really missed something simple or the thing is defective, 'cause the instructions barely mention the stud step...

[Goose]

the stud is stepped larger at the bottom if i remember right..
I will pull mine out later and look ..

[GratefulTread]

Talked with Edelbrock again, they say it should easily thread into the carb. Pulled it off and there are no threads at the bottom. Looks like a defect, I'm taking it back for an exchange. Certainly going to pull the new one out and try it first!

[1980_Cj7]

Talked with Edelbrock again, they say it should easily thread into the carb. Pulled it off and there are no threads at the bottom. Looks like a defect, I'm taking it back for an exchange. Certainly going to pull the new one out and try it first!

Ah ha! I finally found somebody else with luck like mine. Probably only one in a million carbs would come thru with a manufacturing defect like that, and I'd be the lucky one to get it. Sounds like I have competition now though, ha, ha.

[fuzz401]

gee and I am running a 950dp on my 401 and thinking about going to a 1050 carb next

my 950 has 95/99 jets 3.5 PV in front and blocked in the back the 850 I had I could get no color on the plugs

[GratefulTread]

Back from the store- new carb bolted on easy, running great, and with an air filter topping it all off! :lo1l: =D> :mrgreen:

Aside from the obvious, this was a great upgrade to my truck! I hope I can keep my foot out of it long enough to figure out mileage! :?

Thanks to all for the help!

[AMX69PHATTY]

fuzz401,
maybe try some colder spark plugs to see if you can get them to color.
Too hot of a spark plug will not take on color.
:-|

http://home.fuse.net/ckthomas/Spark-Plug-Heat-Ranges.jpg

[fuzz401]

I am useing AR3933 plugs now was useing 63 before the 950 color was not there with the 950 have color with the 63 plugs

[GratefulTread]

Just in case you were wondering....can't keep my foot out of it! :t:

[Goose]

Yea fuzz you might be able to use all that 950.. but it isnt anywhere near stock..and I'm betting it sees way more than 4500 rpm..

Dont get me wrong here.. Big is Good when you can use it.. but bigger doesnt always mean faster..a 950 dp or 1050 on a stock or near stock street engine in a 5800 lb J-10?? that would be a disaster..not to mention be a pain in the ass to tune. however the crisp throttle response and bottom end torque from a properly sized and tuned carb will make the truck seem much faster .. In my not always humble opinion lots of folks would be happier if they defined a performance increase by driveability. Nothing takes the fun out of a fast car/jeep etc than a bunch of nagging annoyances like overheating, loading up, hard to start, no hot starts etc.. to each his own though..

[fuzz401]

6500 to 7000 shifting :roll: